'Cast into the Fire' in the Bible

“Let burning coals fall upon them;Let them be thrown into the fire,Into deep [water] pits from which they cannot rise.

If it has been thrown into the fire for fuel, and the fire has consumed both of its ends and the middle section has been charred, is it suitable or useful for anything?

Every tree that does not bear good fruit is cut down and thrown into the fire.

Even now the axe [of God’s judgment] is swinging toward the root of the trees; so every tree that does not produce good fruit is being cut down and thrown into the fire.”